The primary aims of this research proposal are to fully define the role of adenine nucleotide translocase, and other mitochondrial permease systems during the onset of myocardial ischemia; and, to investigate the biochemical mechanisms by which long chain fatty acids control the activity of these essential enzymes. Based on these investigations, attempts will be made to describe, at the molecular level, the properties of reversible and irreversible metabolic changes that occur in heart cells during ischemia. Throughout this work, biochemical findings will be closely correlated with physiological and ultrastructural data, in an effort to more completely explain the structural and functional relationships during the early stages of ischemia.